And the new skimmers are not only impossible to detect, but thieves don’t have to be anywhere near the gas station to use them.

They are using Bluetooth-enabled skimming devices.

According to Detective Eric Pahlberg, a member of the Sacramento Valley High-Tech Crimes Task Force, thieves can gain access to the majority of gas pumps across the county with several keys that are likely standardized for easy inspection and maintenance.

He added that any devices installed inside the pump are impossible for drivers to detect and tough for law enforcement to find.

“These guys will come in and install a skimmer on the pump. It’ll stay on for a few days and they’ll come back and take it off,” Pahlberg told KCRA 3. “Unless we discover it in the meantime, the gas owner or operator would never even know it’s there.”

Bluetooth-enabled skimmers are already a problem in the Bay Area.

The device collects and transmits data from drivers’ credit cards to the thieves, who can be up 100 yards away from a gas station.

Pahlberg said he has not seen a Bluetooth skimmer in the Valley yet, but they may be out there.

Just last week, thieves tried to break into a pump at the Shell station near Arden Fair Mall, but the owner said his recently installed special locks prevented them from getting access.

“We keep an eye on the pumps almost every day, so anything we see that’s new or odd -- we take care of right away,” owner Balbir Dhillon said.

Pahlberg said the Sacramento Valley High-Tech Crimes Task Force has sent letters to gas stations in the area, urging them to not only change locks but also check the inside of pumps frequently.

He also urges consumers to be on alert by checking their debit and credit card expenses.

“It’s so lucrative that you arrest a couple of people, and there are always more people who are ready to fall right behind them and do the same thing,” Pahlberg said.

Consumers can protect themselves in several ways: pay with cash; check to see if the gas station has changed its locks; and if they’re swiping at the pump, use credit cards rather than debit cards because they better protect against fraud.